The Role of RNA in Tau Aggregation

项目概述：Tau病是一组神经退行性疾病，其特征在于 微管相关蛋白Tau（tau）在尸检患者的大脑中发现。这些病症包括 阿尔茨海默病（AD）、慢性创伤性脑病（CTE）和额颞叶痴呆（FTD）。AD 仅是美国的第六大死亡原因（影响超过570万人），目前没有治愈方法， 预计未来数年病人数目会大幅增加。 tau蛋白病可由促进其聚集的tau蛋白突变（如FTD）或由 细胞外应激物触发tau聚集（如在AD和CTE中）。细胞外应激源如何导致 细胞内tau聚集是未知的。最近的一些观察表明，应力颗粒 (SGs)一种细胞溶质RNA和蛋白质组装体，在细胞应激反应中形成， 在tau聚集体的形成和持久性和操纵SG中的作用可能表明新的治疗方法， 战略布局我提出了一个模型，其中细胞应激源（例如，神经炎症、病毒感染、淀粉样蛋白-b） 促进招募tau的SG的形成。SG产生高浓度的tau和RNA， 并且稳定tau聚集体并有助于它们的毒性。该模型得到了体外和体内实验的支持。 证据表明RNA促进tau聚集，在AD患者中RNA被隔离成tau聚集体 减少SG形成会降低tau毒性。 我的初步数据显示神经炎性化合物引起的应激颗粒， 前列腺素J2与tau共定位。我还通过电子显微镜和硫磺素T荧光 在体外将RNA与tau孵育会导致由成对螺旋丝组成的tau聚集体的形成， 含有RNA的细胞。最后，我通过RNAseq和单分子荧光原位杂交显示， （smFISH）体内tau聚集体含有多种RNA（rRNA、mRNA、snRNA和lncRNA）， 一些RNA比其他RNA更丰富。 本提案的目的1将鉴定和操纵在细胞中与tau蛋白结合的RNA水平。 疾病相关模型系统中的非聚集和聚集状态。成功实现这一目标， 提示1）哪组RNA作为tau聚集的辅因子，2）tau聚集体中的RNA是否相似 和3）特异性RNA的螯合是否有助于tau毒性。本提案的目标2将 操纵SG形成和RNA稳定性，然后测量这些操作如何影响tau蛋白 聚合来这一目标的结果将确定RNA和SGs在形成和持久性中发挥的作用。 tau聚集体。广泛地说，这项提议旨在检验SGs与细胞外应激和细胞外应激之间的联系这一假设。 细胞内tau聚集，希望确定新的治疗策略来治疗衰弱 神经退行性疾病如AD。

PROJECT SUMMARY: Tauopathies are a group of neurodegenerative diseases characterized by aggregates of the Microtubule Associated Protein Tau (tau) found in the brains of patients on autopsy. These disorders include Alzheimer's disease (AD), chronic traumatic encephalopathy (CTE), and frontotemporal dementia (FTD). AD alone is the 6th leading cause of death in the US (affecting more than 5.7 million), no cure is currently available, and the number of patients is expected to substantially increase in the coming years. Tauopathies can be caused by mutations in tau that promote its aggregation (as in FTD) or by extracellular stressors that trigger tau aggregation (as in AD and CTE). How extracellular stressors lead to intracellular tau aggregation is unknown. A number of recent observations indicate that stress granules (SGs), a type of cytosolic RNA and protein assembly that forms in response to cellular stress, might be involved in the formation and persistence of tau aggregates and manipulating SGs could indicate new therapeutic strategies. I propose a model where cellular stressors (e.g., neuroinflammation, viral infection, amyloid-b) promote the formation of SGs that recruit tau. SGs create high local concentrations of tau and RNA that nucleate and stabilize tau aggregates and contribute to their toxicity. This model is supported by in vitro and in vivo evidence suggesting that RNA promotes tau aggregation, RNA is sequestered into tau aggregates in AD patient brains, and that reducing SG formation decreases tau toxicity. My preliminary data shows that stress granules induced by the neuroinflammatory compound, prostaglandin J2, colocalize with tau. I have also shown by electron microscopy and thioflavin T fluorescence that incubating RNA with tau in vitro causes the formation of tau aggregates made up of paired helical filaments that contain RNA. Finally, I have shown by RNAseq and by single molecule fluorescence in situ hybridization (smFISH) that in vivo tau aggregates contain a diversity of RNAs (rRNAs, mRNAs, snRNAs, and lncRNAs) and some RNAs are more enriched than others. Aim 1 of this proposal will identify and manipulate the levels of RNAs that are bound by tau in unaggregated and aggregated states in disease relevant model systems. Successful completion of this aim will suggest 1) what set of RNAs act as cofactors for tau aggregation, 2) whether the RNAs in tau aggregates are similar to SGs, and 3) whether sequestration of specific RNAs contributes to tau toxicity. Aim 2 of this proposal will manipulate SG formation and RNA stability and then measure how these manipulations influence tau aggregation. Results of this aim will determine what role RNA and SGs play in the formation and persistence of tau aggregates. Broadly, this proposal aims to test the hypothesis that SGs link extracellular stress and intracellular tau aggregation with the hope of identifying new therapeutic strategies to treat debilitating neurodegenerative diseases such as AD.